Spark-Ignition Engine Control With Split Injection to Limit Oil Dilution
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Solution Overview
Problem
Spark ignition internal combustion engines using alcohol-containing fuel face significant dilution issues due to increased injection volumes and reduced vaporization, leading to decreased lubrication effectiveness and engine performance.
Innovation Solution
A control device that executes split injection of alcohol-containing fuel into the cylinder during both the intake and compression strokes, controlled by a controller that detects alcohol concentration and ambient/temperature conditions to optimize fuel injection timing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the injection volume of alcohol-containing fuel is increased to maintain output, then the fuel adhering to the inner wall of the cylinder flows down and dilutes the engine oil, but the lubrication effect of the engine oil decreases
Solution Approach 1:
The fuel injection is divided into multiple stages: a first injection during the intake stroke and a second injection during the compression stroke. This segmentation allows the fuel to be introduced at different times when the piston position and cylinder conditions differ, reducing continuous contact with the cylinder wall and minimizing oil dilution while maintaining total injection volume for power output.
2Object-affected harmful factors
If alcohol-containing fuel is used as alternative fuel to gasoline, then carbon dioxide emissions are reduced, but the fuel is less likely to vaporize under low temperature conditions and requires increased injection volume
Solution Approach 1:
A first injection of alcohol-containing fuel is performed during the intake stroke before the compression stroke. This preliminary injection allows the fuel to be introduced when the cylinder temperature is lower, and the fuel can mix with the intake air and be prepared for combustion, compensating for its reduced vaporization tendency at low temperatures.
3Loss of substance
If split injection is executed by dividing fuel injection into intake stroke and compression stroke, then the dilution amount is suppressed, but the injection timing control complexity increases
Solution Approach 1:
The fuel injection is performed periodically at two distinct phases of the engine cycle: once during the intake stroke and once during the compression stroke. This periodic action pattern is easily detectable by the control device using existing crank angle sensors and stroke detection logic, allowing the complex split injection timing to be implemented through systematic periodic control rather than continuous adjustment.
Data Source
AI summary
Provided is a control device for a spark ignition internal combustion engine configured to directly inject alcohol-containing fuel into a cylinder, the control device for an internal combustion engine including a controller configured to control injection timing when the fuel is injected into the cylinder from a fuel injection device, an alcohol concentration detecting part configured to detect a content of alcohol contained in the fuel, and a crank angle detecting part configured to detect rotation of a crankshaft and output a crank angle signal and a top dead center signal, the controller executing split injection of splitting and injecting the fuel into an intake stroke and a compression stroke from the fuel injection device into the cylinder when a concentration of alcohol in the fuel is equal to or greater than a predetermined value.